Radiative cooling enhanced performance of adsorption desalination–cooling system

Adsorption desalination-cooling system (ADCS) is a promising nature-centric technique that co-generates salt-free water, and sub-ambient cooling. However, adsorbents used in the ADCS remain unsaturated with water (50–90 %) due to low evaporator and high adsorption temperatures, often equivalent to 10 °C and ambient temperature, respectively. The present study aims to numerically investigate the integration of radiative cooling with ADCS to decrease the adsorption temperature while employing solar heating for regeneration of the adsorbent bed. The findings indicate that, under solar noon, radiative cooling produces cool water at a temperature of 16.75 °C, achieving an 8.25 °C reduction in the adsorption temperature compared to the ambient temperature of 25 °C. On the other hand, the solar heater produces hot water at a temperature of 85 °C. Consequently, free cooling and heating potentials are harnessed from the surrounding environment for optimizing the performance of the ADCS. Unlike conventional ADCS systems, proposed hybridization improves the saturation efficiency of studied adsorbents significantly: from 42.2 % to 74 % for silica gel; from 13.64 % to 38 % for PS-II; and from 14.12 % to 49 % for GP-Cl-30 respectively. The maximum water production rate of 77.22 kg/day was achieved using unit mass of GP-Cl-30 adsorbent, along with sub-ambient cooling of 188 MJ/day—surpassing the 25.92 kg/day and 63.25 MJ/day of conventional ADCS system performance. With thermodynamic efficiencies ranging from 0.75 to 0.96 and enhancement in overall system productivity demonstrate that the proposed hybridization offers a sustainable, multipurpose solution for coastal cities.